[Mimedefang] Allowing only certain sender/recipient pairs

[WBrown at e1b.org]

mimedefang-bounces at lists.roaringpenguin.com wrote on 08/09/2006 08:43:19 
AM:

> List,
> 
> I have been asked to investigate setting up a solution to allow only 
certain
> senders... to email only certain recipients, with any non-approved
> sender/recipient messages being rejected.  It sounds like the company 
wants
> to look into a "deny-all except that which is specifically allowed"
> framework for email.

That sounds like a nightmare to manage!!
 
> Has anyone ever set up something like this?  What database types were 
used
> to contain the lookup tables for valid sender/recipient pairs?  What 
kind of
> performance hits were encountered?  And I assume "stream by recipient" 
was
> needed to allow a message to be passed to an allowed user, yet not 
passed to
> a disallowed recipient.  What kinds of problems did that create (aside 
from
> the obvious "one message cc'd to 10 people in becomes 10 messages out" 
kind
> of scenario)?
> 
> David - Is this a feature available in the Can-It products?

As a CanIt Pro user, it would be possible, at least for the recipients 
that you want to control being internal users.  Set up a stream for each 
internal user. 

>From the manual:

5.1.1 Holding Unlisted Senders
CanIt-PRO can allow you to decide to only accept mail from a specific list 
of sender addresses, and
to hold mail from all others. This essentially gives you the benefits of a 
challenge-response or sender
opt-in system without requiring that senders perform any extra additional 
actions before sending you
a message.

To use this feature:

1. Go to Rules : Senders and add the addresses of people you wish to 
receive mail from as Always
allow.
2. Enable the Hold mail from any sender not listed in Senders Table 
setting under Preferences
: Stream Settings.
Messages from the addresses you whitelisted will be allowed, and all 
messages from senders not
specifically listed in the Sender Action Table will be held in your 
Pending trap, even if they score
below your spam threshold.